Fluid spray nozzle



I Sept. 10, 1957 D. s. SANBORN 2,805,891

FLUID SPRAY NOZZLE Filed'April 5 1954 2 Sheets-Sheet 2 Ff .4. F 6.

DA 1W5; s. SA/VBORN INVENTOR. I

United States atent FLUlD SPRAY NOZZLE Daniel S. Sanborn, San Diego, Calif., assignor to McCulloch Motors Corporation, Los Angeles, Calif, a corp-sration of Wisconsin Application April 5, 1954, Serial No. 420,774

4 Claims. or. 299-1916 This invention relates to spray nozzles and more specifically concerns fuel injector nozzles, valves, and orifices.

In conventional plunger operated fuel injection systems the pressure in the fuel line between the plunger pump and the injector outlet valve increases substantially in proportion to the square of the speed of the plunger. As the plunger is operated or actuated by a camshaft driven by an engine, it is evident that the plunger speed is in direct proportion to engine speed. This means that with a fixed nozzle orifice area the fluid pressure in the line increases in proportion to the square of engine speed. For example, when the engine speed increases tenfold from low idle at around 500 R. P. M. to high speed at 5,000 R. P. M. the pressure in the fuel line increases approximately one hundred fold. Such a large pressure range introduces many complicating factors into injector operation, among which is the problem of compressibility of the fuel in the line. Compression of the fuel in the line is the direct result of large fluid pressures and is undesirable to the extent that it interferes with proper injection timing and thereby leads to injection lag with resultant ineflicient engine operation. v

Accordingly, it is an object of the invention to provide a novel fuel injector including means for preventing undesired increase in fluid pressure in the fuel line ahead of the injector outlet valve in order that fuel atomization characteristics may be maintained more nearly constant over the speed range of the fuel pump plunger.

It is another object of the invention to provide a novel fuel injector including means for allowing the egress of a measured quantity of fuel from the injector under a pressure which is, for all engine speeds, below the pressure level at which compressibility of the fuel in the line materially interferes with proper injection timing. it is a further object of the invention to provide a novel fuel injector nozzle including novel combined pressure sensitive valve means and a variable area orifice, the size of which increases from zero opening for all pressures below a certain minimum pressure to a maximum opening at maximum pressure, it being a characteristic of the invention that the pressure of the fluid flowing toward the valve cannot exceed a maximum level.

Other objects and advantages of the present invention will be apparent from the following description when taken in conjunction with the attached drawings and appended claims.

Referring to the drawing:

Fig. 1 is a vertical sectional view of the lower portion of an injector nozzle;

Fig. 2 is a horizontal sectional view looking upward from the plane of line 22 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 showing the injector nozzle during fuel injection;

Fig. 4 is a vertical sectional view of a modified injector;

Fig. 5 is a horizontal view taken on line 55 of Fig. 4 looking upward toward the nozzle end of the injector;

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Fig. 6 is a view similar to Fig. 4 showing the nozzle during fuel injection;

Fig. 7 is a vertical sectional view of another modified injector;

Fig. 8 is a horizontal view taken on line 66 of Fig. 7 and looking upward toward the nozzle end of the injector; and

Fig. 9 is a view similar to Fig. 7 showing the nozzle during fuel injection.

Referring now to Figs. 1 and 2, the injector is indicated at 10, with the upper end portion thereof cut away. The injector includes a housing -11 surrounding a nipple or first ducted member 12 and a nut or second ducted member 13, members 12 and 13 being juxtaposed in end-to-end relation. Duct 14 in nipple 12 extends vertically through the nipple, and the lower end 15 of the duct communicates with the upper ends of several branch ducts such as ducts 16a, 16b, 16c, 16d formed in the seat element or nut 13. The latter ducts may be spaced degrees apart and branch outwardly and downwardly within nut 13 to communicate with an annular chamber 17 formed at the lower end of nut 13.

The annular chamber 17 surrounds the cylindrical surface 21 of an abutment member 2! which forms the actual seating surface of seat element 13 and is disposed centrally therein. The lower surface or end 22 of member 29 may be flattened or curved very slightly to form a transversely extending seating face, a portion of which is adapted to support a thin fiexible plate or disc 25 in fluid sealing engagement.

The plate 25 extends transversely across the lower end face of seat 13 and is centrally apertured to form a fluid guide port 26 disposed adjacent the end 22 of abutment member 2%). The plate includes an inner annular portion 27 having a top surface 27a which is normally urged against the annular surface 28 of face 22 lying between the cylindrical wall 21 of post 2i} and the boundary wall 2? of port 26. The plate also includes an annular portion 30 lying adjacent chamber 17 and extending between the cylindrical wall 21 of post 29 and the cylindrical outer wall 29a of chamber 17. The outer annular portion 31 of plate 25 extending radially outwardly beyond portion 30 is're'taine between the outwardly disposed loWer annular surface 32 of nut 13 and the annular lip 33 at the lower end of housing l1. V

It will be noted that the plate 25 is mounted in such a way that the annular portion 27 thereof is normally urged against the face 22 of abutment member 20 in fluid sealing engagement. This may be done in a number of Ways, for example, the plate may be a flat plate and the outer portion 31 thereof may be mounted in such a way as to be displaced upwardly'beyond the plane of port 26. Alternatively, a plate dished toward face 22 may be used, and may be drawn into a horizontal plane by the upward force'exerted by lip 33 and the downward force exerted by surface 22, in order to provide the required contact force against surface 22., Additional compression spring means may also be used between the lip 33 and the portion 31 of the plate to urge the latter toward surface 22. i p i v The plate 25, abutment member 20 and port 26 function together in such a way as to serve as a'valve, an orifice, a fluid guiding means and a pressure regulating means for limiting, regulating, guiding, and atomizing the flow of injected fluid and for regulating the fiuid pressure within chamber 17, ducts I4 and 16,"and fuelline 37. Fuel injection is controlled by'the usual remotely positioned fuel pump '35 having a plunger 36 operated by a cam 38 which is rotated in synchronism with the engine. It will be understood that the fuel pump 35 controls the time and duration of injection of supplying fuel under pressure to line 37 leading to injector 10 during the pumping stroke of plunger 36. The plunger 36 controls communication of a feed port supplied with fuel from line 39 leading from a remote source of supply with either a discharge port communicating with line 39 or a spill port (not shown) which returns to the fuel to thesource of supply.

Fuel injection is initiated by plunger 36 which is operated by cam 38 to displace fluid in line 37 toward injector 16. The rise in pressure in line 37 is transmitted to annular chamber 17 via ducts 14 and 16, and exerts a downward force on portion 30 of plate 25. When the latter force exceeds theupward force exerted on the plate as described supra, the portions 27 and 3% of the plate are displaced downwardly by an amount proportional to the net downward force on the plate, resulting in the formation of a ring-shaped orifice 40 between the annular surface 28 of member 20 and the displaced annular surface 27a of plate 25, as shown in Fig. 3. 'The size of orifice 40 depends on the amount by. which the downward force on plate exceeds the upward force thereon. The amount by which the portion 27 of plate 25 overlaps end face 22 of abutment member 20 may be made small in order that the fluid pressure exerted on the plate is not materially increased when the plate is displaced downwardly and so that fluid pressure additional exerted on the annular overlapping surface 27a of plate 25 will be minimized. Also, the size of the fluid guide port 26 is made large by comparison with the maximum size of orifice 'in order that the port 26 does not act as a separate orifice to adversely influence the function of orifice 40.

It will be noted that the size of annular orifice 40 tends to increase as the pressure in line 37 increases. Increasing the size of orifice 40 tends to relieve the pressure in chamber 17, ducts 14 and 16 and line 37. Therefore, the plate 25, port 26, and surface 22 of member 20 coact in such a way as to provide not only a valve, the operation of which is controlled by the timing of the pressure waves reaching plate 25, and an injection orifice '40, the size of which is controlled by the pressure of the fluid in chamber 17, but also a means for limiting the pressure rise of fluid in chamber 17 and line 37. Thus the combination plate valve and variable orifice 40 coact to allow injection of fuel in timed relation to the operation of the engine and at the same time to preclude the development of excessively high pressures which other- 'wise would give a degree of atomization variable with flow rate and would also lead to injection lag due to compressibility of the fluid fuel.

The guide port 26 serves to guide the exit of the fuel escaping from orifice 40 and to redirect the flow of fuel in a generally vertically downward direction. Arrows 42 and 43 indicate the general path of fuel increments as they leave the nozzle end of the injector 10. It will be understood that modifications of the guide port 26 may be made to obtain the desired shape of the spray pattern 42 and 43. r V 7 Figs. 4, 5, and 6, and 7, 8 and 9 illustrate two modified forms of my invention. In Figs. 4, 5 and 6 there is illustrated the nozzle end of "an injector which includes a housing surrounding a ducted body member 51 having a centrally located vertical duct 52 formed'therein. An annular cavity or recess 53 is formed in the lower end of member 51, all portions of the chamber being spaced radially outwardly from an annular abutment 54 surrounding duct 52. 1

A thin rigid plate or disc 55 extends transversely across the lower end of member 51 and is urged into contact therewith by a spring washer 56. A resilient plate similar to plate 25 used in Fig. 1 may alternatively be utilized.

The washer is apertured'and beveled to form an inclined,

narrow annular member having an upper lip or edge 57 i in contact with the lower surface 58 of plate 55 andhaving a. lower lip or edge 59 in contact with and retained by the inwardly turned lip 60 of the circumjacent wall of 4 the housing 50. The function of washer 56 is to bear against the underside of plate 55 and resiliently urge it upwardly into normal fluid sealing engagement with the smooth annular bottom surface 61 of abutment member 54.

Plate 55 has formed therein a plurality of orifices 62 which are symmetrically arranged in a circular pattern in plate 55 and equispaced from one another. Non-symmetrical arrangements may also be used to vary the spray pattern. Each of the orifices 62 communicates with the annular cavity 53. In operation, plate or disc valve 55 is forced downwardly to open up ring shaped aperture 63 between the bottom surface 61 of member 54 and the top surface of plate 55 only after the downward force exerted plate 55 by the pressure of fluid in duct 52 exceeds the upward force exerted on plate 55. When aperture 63 is opened up, fluid under pressure flows from duct 52 into cavity 53 and then escapes through orifices 62 forming separate injection spray patterns 64.

In other words, the particular structuredescribed not only acts as a valve, but also comprises a variable area aperture with the function of preventing undesired fluid pressure increase in the fuel line.

It will be noted that once plate 55 is displaced downwardly, fluid pressure is additionally exerted on that por tion of the top surface of plate 55 lying radially outwardly from the walls of duct 52. This additional fluid pressure exerts an additional downward force on the plate 55 which acts to displace the plate downwardly by an additional amount. Therefore, when the pressure is relieved in duct 52 as a result of cessation of thepumping stroke of plunger 36 of the fuel pump 35, the plate valve 55 will not return completely upwardly to completely close aperture 63 until the pressure in duct 52 is reduced to considerably below the level required to initially displace plate 55 downwardly. This feature provides ,an automatic pressure lag in closing of the aperture 63 and therefore constitutes an automatic means for reducing the line pressure below the opening pressure to reduce any tendency toward leakage between injection strokes of the fuel pump plunger.

Figs. 7, 8 and 9 are similar to Figs. 1, 2, and 3 in all respects except as to the configuration of that portion of the thin plate valve 76 adjacent the lower surface 22 of post 2% The mid portion 71 of the plate is dished downwardly away from surface 22 to form a small fluid receiving plenum chamber 73 anterior to a plurality of holes '74 formed in portion 71 of the plate. The holes 74 may be made small enough so that the sum of their areas is of the same order of size or smaller than the average ring-shaped area of the aperture 75 formed between the edge 7 6 of bottom portion 22 of post 2%) and that portion 77 of plate 7% normally in contact therewith when fluid pressure has displaced plate 7% downwardly. Thus, the holes 74 act as orifices resulting in nearly constant fuel atomization, while the aperture 75 serves to admit fluid to plenum chamber 73. p 7 I It is noted that the size of aperture 75 is governed by the amount of downward pressure exerted on plate ,70

. by fluid in chamber 17 in excess of the upward force excited by the plate resulting from its resiliency. When the size of aperture 75 is substantially smaller than the collective size of orifices 74, the principal pressure drop will occur across aperture '75, which will then serve to control the pressure that can develop in chamber 17 and in the fuel feed line, as explained in connection with Figs. 1, 2, and 3. I V 7 When aperture 75 is opened up, fluid under pressure escapes from chamber 17 into chamber 73, from which the fluid is expelled under pressure through orifices 74, thereby forming a plurality of indivi ual injection fuel spray patterns 8%.

Obviously many modifications of the invention may be made without departing from the scope thereof, and

therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In a fuel injection nozzle: a body having in its inner end an annular recess, there being an abutment within said recess projecting from the bottom wall thereof and having at the extremity thereof an annular face, and a circumjacent wall having an inwardly faced annular shoulder contiguous to the periphery of said recess; an orifice-forming disc extending across said recess, the peripheral portion of said disc being spaced inwardly from said annular shoulder; and an annular spring between said annular shoulder and the peripheral portion of said disc, urging said disc inwardly of said recess so as to bring an annular portion of said disc into engagement with said annular face of said abutment, said disc having a spray orifice therein on one side of said annular face, said orifice communicating directly with the space exterior to the nozzle and contiguous to the outer face of said disc, and said body having therein a fluid inlet passage for delivering fluid to said spray orifice, the mouth of said fluid inlet passage being on the opposite side of said annular face of said abutment from said spray orifice so that the fluid from said mouth of said passage flows across said annular face to said orifice.

2. In a fuel injection nozzle: a body having in its inner end an annular recess, there being an abutment within said recess projecting from the bottom wall thereof and having at the extremity thereof an annular face, and a circumjacent wall having an inwardly faced annular shoulder contiguous to the periphery of said recess; an orifice-forming disc extending across said recess, the peripheral portion of said disc being spaced inwardly from said annular shoulder; and a dished annular spring between said annular shoulder and the peripheral portion of said disc, urging said disc inwardly of said recess so as to bring an annular portion of said disc into engagement with said annular face of said abutment, said disc having a spray orifice therein on one side of said annular face, said orifice communicating directly with the space exterior to the nozzle and contiguous to the outer face of said disc, and said body having therein a fluid inlet passage for delivering fluid to said spray orifice, the mouth of said fluid inlet passage being on the opposite side of said annular face of said abutment from said spray orifice so that the fluid from said mouth of said passage flows across said annular face to said orifice.

3. In a fuel injection nozzle: a body having in its inner end an annular recess, there being an abutment within said recess projecting from the bottom wall thereof and having at the extremity thereof an annular face, and a circumjacent wall having an inwardly faced annular shoulder contiguous to the periphery of said recess; an orifice-forming disc extending across said recess, the peripheral portion of said disc being spaced inwardly from said annular shoulder; and an annular spring between said annular shoulder and the peripheral portion of said disc, urging said disc inwardly of said recess so as to bring an annular portion of said disc into engagement with said annular face of said abutment, said disc having a spray orifice therein between the periphery of the disc and said annular face, said orifice communicating directly with the space exterior to the nozzle and contiguous to the outer face of said disc, and said body having therein a fluid inlet passage for delivering fluid to said spray orifice, the mouth of said fluid inlet passage being circumscribed by said annular face of said abutment so that the fluid from said mouth of said passage flows across said annular face to said orifice.

4. A fuel injection nozzle as defined in claim 3 wherein said spring is a dished annular spring applying force evenly to the peripheral portion of said disc.

References Cited in the file of this patent UNiTED STATES PATENTS 1,567,051 Gronkwist Dec. 29, 1925 2,084,057 French June 15, 1937 2,088,614 Schey Aug. 3, 1937 2,144,874 Edwards Jan. 24, 1939 2,308,504 French Jan. 19, 1943 2,733,960 Borford Feb. 7, 1956 FOREIGN PATENTS 348,712 Great Britain May 21, 1937 909,736 France Jan. 7, 1946 

